Electric fuse.



R0. 792,530. PATENTED JTNE 13, 1905e N. MARSHALL.

ELECTRIC FUSE.

APrLIouIoI FILED Jun 27. 1903. nzxnwm un 2o, 1905.

/N VEN T05' #me VV/ TML-ss Es UNITED STATES Patented June 13, 1905.

PATENT OFFICE.

NORMAN MARSHALL, OF NEVTON, MASSACHUSETTS.

ELECTRIC FUSE.

SPECIFICATION forming part of Letters Patent No. 792,530, dated June 18, v1905.

Application filed June 27, 1903. Renewed May 20, 1905. Serial No. 261,423.

To all whom t may con/cern:

Be it known that I, NORMAN MARSHALL, of Newton, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Electric Fuses, of which the following is a speciiication.

My invention relates to that class of electric fuses or cut-outs in which an auxiliary fuse-wire is employed to indicate the condition ot' an inclosed main fuse-wire, and more especially to the arrangement and disposition of the auxiliary fuse-wire which enables the parts to be readily and economically assembled and results in a simple and efiicient construction.

The features of invention consist in the construction and arrangement set forth in the claims and will be best understood by reference to the accompanying drawings, in whichf Figure l is a sectional view of a fuse embodying the invention. Fig. 2 is an enlarged view of the cup for retaining the auxiliary fuse in place. Fig'. 3 is a similar View of a modiied form of retaining-cup, and Fig'. 4 is a View indicating the manner of assembling' the parts.

As shown in the drawings, the main fusewire A of the fuse is inclosed in a tubular casing B, which may be of any suitable material, the ends of the casing being closed by metallic caps O. The main fuse-wire A extends through the tubular casing and is connected with the terminals D, secured to the caps O. The casing B is lilled with a finelydivided non-conducting material E, which surrounds the main fuse-wire.

The parts thus far referred to may be of any suitable Well-known construction and arrangement, such as is usually employed in the class of fuses to which the invention relates.

The auxiliary indicating-fuse consists of a fine wire F, of any suitable metal, located within the casing B and having its ends in electric connection with the main fuse-wire in any suitable or well-known manner. As shown, the auxiliary wire extends along the inner surface of the casing B and has its ends in engagement with the metallic caps C.

The casing B is provided with an opening Gr through its walls, and a cup H extends through said opening. The auxiliary wireF passes through the walls of the cup H and is held in position across the opening G by said cup. In assembling the parts the wire F is threaded through the walls of the cup H, as indicated in Figs. 2 and 3, and the ends ot` the wire then are drawn into parallel relation, so that they may-be thrust through the opening G, as indicated in Fig. 4. The ends ot' the wire are then drawn outwardly in opposite directions to the opposite ends of the casing and the cup brought into position in the opening G, through which it extends, as indicated in Fig. l. The ends of the wire F may then be bent over the ends of the casing B in position to be engaged by the metallic caps or may be otherwise connected with the main fuse\vi1e and the fuse iinished in the usual way.

The cup H may be of any suitable form or construction. In Figs. 1, 9 and a the cup is shown provided with cylindrical walls and with a closed bottom wall. In Fig. 3 the cup is shown in the form of an open-ended tube having` the greater portion of its walls cut away.

The cup H may be filled with an explosive, expansive, or discolorable material or with any other material for indicating the disruption of the main fuse. I prefer, however, to employ an explosive in the cup H and to cover the cup with a thin mesh of asbestos I. Vith this construction the asbestos will be blackened upon the burning of the explosive, but will prevent any spark from coming through to the outside ot' the fuse. This construction of indicating means may be used with advantage in any form of fuse in which the disruption of the main fuse-wire will cause the explosive to be lired. If desired, the indicating material may be entirely omitted, in which case the condition of the indicating-fuse may be observed through the cup H in the opening G.

Upon the blowing of the fuse the auxiliary indicating-wire is heated and melted and acts upon the indicating' material in the cup in case such material is used, and thus the blowfuse-Wire, an inclosing casing for the same i having an opening through its Wall, a cup-extending through said opening, an auxiliary f fuse- Wire Within the casing and passing through said cup, and a material in said cup for indicating the disruption of the main fuse.

3. In an electric fuse or cut-out, the combination. With an inclosing casing and a main fuse-Wire, of an explosive means for ring the same upon the disruption of the main fuse- Wire, and an asbestos meshl covering said eX- plosive.

InI testimony whereof I have affixed my signature in presence of two Witnesses.

NORMAN MARSHALL. Vitnesses:

IRA L. FISH', KATHARINE A. DUGAN. 

